Electrical plug



June 17, 1969 KARL'FRIEDRICH SCHMITT E 3 ELECTRICAL PLUG Filed Jan. 16,1967 FIGJ.

6 u 79 I0 76 J I5 l9 2o FIG.3.

ATTORNEYS United States Patent US. Cl. 33942 Claims ABSTRACT OF THEDISCLOSURE An electrical plug made from a hollow housing, a body memberwithin the housing, and two half-shell members attached to one end ofthe housing. The body member has a projection extending from one endthereof between the half-shell members with a transverse alignment borein the projection. Each half-shell member has a corresponding alignmentbore, and the three parts are secured together by a bolt passing throughthe three alignment bores. The half-shell members are aligned withrespect to the housing by means of beads on the interior surface of thehalf-shells which engage a recess in the exterior surface of thehousing.

Background of the invention The invention relates to electrical plugsconsisting of an insulating body containing electrical sockets orprongs, a housing surrounding the insulating body, and two halfshellsattached to one end of the housing to receive electrical conductors.

Connector sockets are known whose insulating bodies are constructed oftwo identical halves. These halves contain recesses in which thesockets, together with their connecting leads, are disposed. Both halvesof the insulating body are held together by means of a screw and a nut.

These prior art connector sockets, however, do not always permit safeinstallation of the connecting leads, since the sockets sometimes changetheir position while the two halves are being placed together.

It is the object of the present invention to provide an electrical plugof the above-noted type which guarantees safe installation, and whichfurthermore provides a safe contact even in very dirty surroundings.

Summary of the invention The above-noted object of the invention isachieved by providing a projection on the insulating body which extendsbetween the two half-shells, with a transverse alignment bore in theprojection and a pair of matching transverse alignment bores in the twohalf-shell members, and beads on the inner surface of the two half-shellmembers to engage a recess on the outer surface of the housing. Theassembly is held together by a bolt passing through the three transversealignment bores.

In a preferred embodiment of the present invention, in which socketcontacts are contained within the insulating body, a coaxial guidechannel is provided in front of each contact socket, and a pair ofspring loaded slides close the front of the sockets to prevent dirt fromentering. The front surface of each slide is beveled so that the slidewill be pushed aside when prongs are inserted into the sockets.

Brief description of the drawings FIGURE 1 is a plan view of one bodymember of the invention in partial cross section.

FIGURE 2 is a plan view of the body member of 3,451,036 Patented June17, 1969 for use in combination with the plug shown in FIG- URE 2.

Description of the preferred embodiment Referring to FIGURE 1, contactsockets 1 are selfcleaning multiple safety contacts with independentlyflexi- 'ble individual contacts, and are floatingly connected by meansof screws 2 within an insulating body 3. The insulating body contains,on the side toward the connecting lead, a projection 4 with a transversealignment bore 5. A coaxial guide channel 6, which in its rest positionis closed by slides 7, is disposed in front of the contact sockets.Slides 7 prevent dirt from entering the contact sockets. Duringoperation, the slides 7 are pushed by the plug prongs 8 (FIGURE 3) underpressure of the springs 9 into a transverse channel 10. The displacementof slides 7 is facilitated by the beveled top surface 11 of the slides.When the plug prongs 8 are inserted, the slides come to rest againstindentations 12 in the plug prongs and thus provide a mechanical safetylock, which can be manually disengaged by applying sufiicient withdrawalpressure to the prongs.

The above-noted embodiment is assembled as follows:

First, the essentially cylindrical socket insert 13 (FIG- URE 1) isinserted from the rear into a hollow housing 14 (FIGURE 2). There,socket insert 13 rests against a frontal, inwardly directed collar (notshown in the drawings). Then, the upper half-shell 15, into whose bore16 a hollow rivet 17 with a nut 18 attached thereto had previously beenattached, is placed with its bead 19 in the recess 20 of the housing.Subsequently, the lower half-shell 15, which is identical to the upperhalf-shell 15, is also placed with its bead in the recess of thehousing. Finally, the machine screw 21 is placed through the bore of thelower half-shell 15', through the bore 5 and through the bore 16 of theupper half-shell 15 and is screwed into the nut 18. The upper ends ofthe half-shells are shaped to provide a lead wire clamp for the leadwire, and pressure is applied to this lead wire clamp by machine screw21. As protection against electric shock hazard, the housing isprovided, on its plug-insertion side, with a protective collar 22 whichreceives the insulated base 22' of the plug 23.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes, andadaptations.

What is claimed is:

1. An electrical plug comprising, in combination:

(A) a hollow plug housing member having an annular recess in theexterior surface thereof near one end thereof;

(B) a pair of half-shell members joined to the exterior surface of saidhousing member at said one end thereof, each of said half-shell membershaving a bead on the interior surface thereof near one end thereof forengagement in said annular recess, and each of said half-shell membershaving a transverse alignment bore;

(C) a plug body member within'said housing member, said plug body memberhaving a projection extending from one end thereof between saidhalfshell members, and said projection having a transverse alignmentbore; and

(D) means passing through the three transverse bores, while the same arein alignment with each other and while said beads of said half-shellmembers are received in said recess for securing said two halfshellmembers, said housing member, and said body member together to form aunified electrical plug.

2. An electrical plug as defined in claim 1, wherein said means passingthrough the three transverse bores comprises a machine screw and a nut.

3. An electrical plug as defined in claim 1, wherein both half-shellsare identical.

4. An electrical plug as defined in claim 1, wherein said housing memberand body member are cylindrical in shape.

5. An electrical plug as defined in claim 1, and further comprising acollar of insulating material attached to the other end of said housingmember.

6. An electrical plug as defined in claim 2, wherein said nut is mountedon a hollow rivet inserted through the bore of one of said half-shells.

7. An electrical plug as defined in claim 1, and further comprising alead Wire clamp formed on the other end of said half-shell members.

8. An electrical plug as defined in claim 1, and further comprisingcontact sockets disposed within said plug body member.

9. An electrical plug as defined in claim 8 and further comprising acoaxial guide channel disposed in front of each contact socket, a pairof slides disposed within a transverse guide channel and movable into acorresponding one of said coaxial guide channels, said slides having afrontally beveled surface, and spring means urging said slides towardsaid corresponding coaxial guide channels.

10. An electrical plug for use in combination with the electrical plugdefined in claim 9, comprising a second 5 body member, two prongs joinedto said second body member and projecting therefrom, said prongs beingpositioned to engage said contact sockets in the first mentioned bodymember, and indentations in said prongs for engaging said slides whensaid prongs are inserted into said contact sockets.

References Cited UNITED STATES PATENTS *MARVIN A. CHAMPION, PrimaryExaminer.

J. R. MOSES, Assistant Examiner.

US. Cl. X.R.

